Efficacy of native fluorescent pseudomonads in management of bacterial wilt of tomato under the mid hill conditions of Meghalaya, India

Abstract

Bacterial wilt caused by Ralstonia solanacearum is of common occurrence in commercially grown solanaceous vegetables in acidic soils. The extent of damage ranges from 60-80% depending on the crop variety and growing season in North East India. The wide host range, diverse race and biovar of R. solnacearum, the management of bacterial wilt through resistant cultivar is not so encouraging. In order to develop efficient bio-control management strategy of R. solanacearum, two biocontrol agents viz. Pseudomonas fluorescens (USR 9.2) and P. putida (PC) with ability to produce antibiotic, metabolite and native to the soils of Meghalaya, India were used in this study. In-vivo evaluation on tomato plant at Nongpoh and Umiam, Meghalaya, India against R. solanacearum was carried out following different methods of application of the bio-agent i.e. individual application as seed treatment or root dip treatment or soil application and in combination as seed treatment + root dip treatment and as seed treatment + root dip treatment + soil application. Both pseudomonad fluorescents were found to have suppressive effect against R. solanacearum isolates under in-vivo in the mid hills condition of Meghalaya. The study revealed that soil treatment for individual application was most effective, whereas seed treatment + root dip treatment + soil application was found most effective for application methods in combination. However, the effect of the bio-agent on the yield was found maximum when applied in combination i.e. seed treatment + root dip treatment and seed treatment + root dip + soil application rather than single application alone.